This program addresses the synergistic interactions of combustion-generated organic pollutants and particles that increase their chemical and, biological activity. Program goals include: 1) understand the relationships'.between'the. origin, mechanisms of formation, nature of emissions;biological availability;and biological activitybttoxic combustion by-products such that;2) improved, health effects-engineered, thermal treatment technologies can be developed;and 3) intelligent fisk^based decisions can be made concerning on-site versus offsite treatment and thermal versus non-thermal treatment options of Superfund Wastes. Our research will focus on the origin and health impacts of four classes of pollutants: 1) combustiongenerated ultra-fine particles (UFPs), 2) persistent free radicals (PFRs), 3) chlorinated hydrocarbons (CHQs), and 4). brorninated hydrocarbons (BHGs). Combustion generates UFPs or "nanoparticies" with diameters less than?0i1:rnicrcons-.whieh;have7been linked to:the'health impacts, of airborne PM2.5.1 OHCs and;BHCs consistently rankamong the most significant chemicals of concern at Superfund sites, and their thermal degradation is known to create toxic by-products including polychlorinated and brorninated dibenzcp-dioxins and dibenzofurans. We will specifically focus on the role of chemisorption.of CHCs and BHCs on UFPs to form surface-stabilized PFRs that can generate oxidative stress in exposed individuals as well as be key intermediates in the formation of new pollutants. PFRs are a new class of pollutants that may be responsible for some of the observed health impacts of UFPs and has been the subject of unique research by key members of our research team for the past 3 years. In this proposal, a multidisciplinary team of biomedical, biological, chemical, and engineering researchers in addition to environmental policy scientists will address the lihksvbetween human health impacts of toxic;air pollutants and combustion/thermal processing of hazardous wastes., this program is truly interdisciplinary as!it has a specific goal of establishing the nature of this link, and as such will require each group of researchers to go beyond their traditionally narrow veins of research and to integrate their understanding. The program consists of: three biomedical projects, three non-biomedical projects, four research support cores, an administrative core, a research translation core, a community outreach core, and a training core.